Question

an electromagnetic wave has an electric field with peak value 120. What is the averge energy delievered to a surface

Answer 1

Answer:

The average energy delivered to a surface is 19.116 W/m².

Explanation:

Given;

maximum electric field, E₀ = 120 v/m

The average energy delivered by the wave to a surface is given by

$I_{avg} = \frac{c\epsilon_ o E_o^2}{2}$

where;

c is the speed of light, = 3 x 10⁸ m/s

ε₀ is the permittivity of free space = 8.85 x 10⁻¹² c²/Nm²

$I_{avg} = \frac{c\epsilon_ o E_o^2}{2} \\\\I_{avg} = \frac{(3*10^8)(8.85*10^{-12})( 120)^2}{2}\\\\ I_{avg} =19.116 \ W/m^2$

Therefore, the average energy delivered to a surface is 19.116 W/m².